Mac OS X comes bundled with some stellar software, but one of the most powerful apps in the Mac arsenal is tucked away in the Utilities folder. Disk Utility is a complete disk management toolkit, with powers that extend way beyond formatting.
You can use it to back up your entire system, create bootable DVDs, repartition drives – even restore your system at installation. You can use Disk Utility to create a standard disk image for multiple systems, shaving hours off the install process.
We’ll delve deep into Disk Utility, using it to fix common problems and protect your system, without third-party software, expensive backup tools or command line tricks.
1. Mounting volumes External drive didn’t mount when your machine booted up? Time to dig out Disk Utility. Launch it from the Applications/Utilities folder in Finder. You should see all connected drives in the left hand pane. Select the unmounted drive and click the Mount button in the tool bar.
2. Unmount volume or partition The Mount button is a toggle – you use the same button to mount or umount drives. So, if an external drive refuses to eject you can open Disk Utility and try unmounting it. Unmounting kills all system activity in process, so it should work. The same thing goes for unruly disk partitions.
3. Erase a drive Need to start again with an external drive or USB stick? In Disk Utility select the volume to blitz, click the Erase tab, then the Erase button. This reformats the drive using the chosen parameters, renaming the disk if you enter a new volume label. Your Mac can now write to the drive as though it’s clean.
4. Secure old data The problem with using Erase is that your old data is still there. If you want to forensically remove it, click the Security Options button instead of Erase. You’re then given several options to choose from, including 35-Pass Erase. Zero Out Data, which we recommend, simply writes 0 over all your old data.
5. Erase rewritable media Disk Utility can even reformat old rewritable CDs and DVDs. Insert the media into your optical drive and select the volume in Disk Utility. You can choose Quickly or Completely. Although the second option may take about an hour it will ensure maximum space is recovered.
6. Create a partition Disk partitions are discreet sections of the same disk that behave like single, logical drives. It can be handy to partition a new drive for contiguous media storage. Select the target drive, click the Partition button and click Add Partition. Remember though – the drive will be erased and reformatted.
7. Resize existing partitions In the OS X 10.5 version of Disk Utility, you can resize existing partitions in the Partitions tab as easily as resizing a window. We do recommend you don’t try this on mounted volumes and that you always backup your system first. Speaking of which...
8. Create and burn disk images Click on the New Image button in the main toolbar to create a .dmg format disk image of a volume – handy for creating portable backups of CDs and DVDs. To burn back to DVD click the Burn button with a blank, writable disk in the optical drive and choose the image you created earlier.
9. Create a bootable system disk You’ll need a dual-layer DVD writer. Go to File➝New➝Disk Image From
10. Secure disk images When creating an image of sensitive data, add extra protection by encrypting the image. In the New Image dialogue, choose 128 bit or 256 bit from the encryption drop-down. You’ll be prompted to select a password, which will be required when you want to reaccess the image later on.
11. Direct back up from Disk Utility You can use the New Image tool to create a compressed system backup. Or use the Restore section of Disk Utility to back up a full disk to an external drive, including USB media. Go to the Restore tab and drag your startup volume to the Source box. Set your external drive as the destination.
12. Back up from Time Machine Time Machine performs a similar backup job on a schedule. To configure it, click the Time Machine icon on your Mac’s main menu bar, click Choose Backup Disk and a destination. Finally, switch Time Machine on to start creating a backup, which will be updated daily.
13. Restore a backup You can restore a backup in Disk Utility’s Restore section during a fresh install. Boot from your Mac OS X Install disk and choose Disk Utility from the Utilities menu. Select the backup as the source and your target, startup drive as the destination.
14. Restore during OS X installation If you have a Time Machine backup there’s a quicker way to restore your old system. Go to the Utilities menu. Choose Restore System from Backup from the menu and browse for your Time Machine backup. You’ll even be able to choose which backup version to restore from.